The downside of my celebrity is that I cannot go anywhere in the world without being recognized. It is not enough for me to wear dark sunglasses and a wig. The wheelchair gives me away.

I believe that the long-term future of the human race must be space and that it represents an important life insurance for our future survival, as it could prevent the disappearance of humanity by colonizing other planets.

One might think this means that imaginary numbers are just a mathematical game having nothing to do with the real world. From the viewpoint of positivist philosophy, however, one cannot determine what is real. All one can do is find which mathematical models describe the universe we live in. It turns out that a mathematical model involving imaginary time predicts not only effects we have already observed but also effects we have not been able to measure yet nevertheless believe in for other reasons. So what is real and what is imaginary? Is the distinction just in our minds?

I think the universe was spontaneously created out of nothing, according to the laws of science. It has no beginning and no end.

Nothing is better than reading and gaining more and more knowledge.

My first popular book, 'A Brief History of Time,' aroused a great deal of interest, but many found it difficult to understand.

Sometimes I wonder if I'm as famous for my wheelchair and disabilities as I am for my discoveries.